Fixed wireless systems are finding use as an alternative to wired phone systems in many areas of the world. These systems use a permanently installed two-way radio located on the customer's property to communicate with a base station, which is connected to a landline telecommunication network, such as the U.S. Public Switched Telephone Network (PSTN). Such systems have helped to reduce the expense involved in providing communications when existing facilities are limited or the terrain is remote or inaccessible. The use of such wireless systems makes access to telephone networks possible in areas that would not otherwise have such access.
The radio system used by the customer is typically comprised of a phone interface, a power supply, a radio unit, an antenna, and a cable interconnecting the radio unit to the antenna. In such a system, the radio unit is connected by cable to an antenna, such as at a centrally located antenna site or other remote antenna. From there, radio frequency transmissions are broadcast to another antenna connected to the base station and thence to the telecommunications network. In the installation of the customer-premise radio unit, measurement of the performance of the cable (e.g. transmission loss of the cable) interconnecting the radio unit to the antenna is necessary. Such performance information is used, in turn, to calibrate the radio unit, in order to ensure appropriate performance of the radio unit, cable and antenna combination. Measurement of the cable performance (e.g. transmission loss) requires personnel with training and skill to conduct the measurements, consumes technician time, and requires test equipment that has to be transported to the installation site. Furthermore, it is preferable that the measurement be made after the cable is installed, for best accuracy, but the two ends of the cable are then often far apart, and accessibility is much more difficult.
In addition to the required cable performance measurements during installation of the radio system, conventional methods require later measurements, as well, due to changes in cable performance, such as those related to changes in environment, weather, age of facilities, etc. that necessitate re-testing of a cable, as well as re-calibration of the radio unit. The need for additional testing may be complicated in such cases as where customer-based radio units are installed at remote or access-limited locations. Any delay in testing which may result can translate into sub-optimal performance of the radio and antenna combination and may result in poor transmission quality. As a result, radio and antenna installations that experience changes in cable parameters may perform poorly until a technician with the proper training and equipment is able to re-test and re-calibrate the cable and transmitter.